Constant velocity coupling

Abstract

A constant velocity joint comprising two concentric couplings, a first coupling comprising an inner member, an intermediate annular member and an outer annular member, the members being concentric. The inner member of the second coupling is common to the outer member of the first coupling. The members of the couplings are constrained to rotate one with respect to another and the outer member of the second coupling is constrained to rotate angularly in respect of the common member in a way that is the mirror image of the rotation of the inner member with respect to the common member.

The invention claimed is: 
     
       1. A constant velocity joint comprising first and second couplings wherein
 the second coupling is disposed concentrically around the first coupling, each coupling comprising an inner member, an outer annular member and an intermediate annular member between the inner and outer members; 
 the members of both couplings are disposed around a common first axis and having a common centre on the common first axis; 
 the outer annular member of the first coupling is also the inner member of the second coupling thereby being a common annular member of both the first and second couplings; 
 the inner member of the first coupling has an outer spherical periphery and the intermediate member of the first coupling has an inner periphery in which the outer periphery of the inner member of the first coupling is received; 
 the intermediate member of the first coupling has an outer spherical periphery and the common annular member has an inner periphery in which the outer periphery of the intermediate second member is received; 
 the common annular member has an outer spherical periphery and the intermediate annular member of the second coupling has an inner periphery in which the outer periphery of the common annular member is received; 
 the intermediate annular member of the second coupling has an outer spherical periphery and the outer annular member of the second coupling has an inner periphery in which the outer periphery of the intermediate annular member of the second coupling is received; 
 the outer peripheries and the inner peripheries being concentric about the common centre and complementary to one another; 
 the intermediate annular member of the each coupling is constrained by a first pair of opposed axles to rotate with respect to the inner annular member of the coupling on a first axis perpendicular to the common axis and by a second pair of opposed axles with respect to the outer member of the coupling on a second axis perpendicular to both the common and the first axis; and 
 wherein the first axis of the outer coupling is the same as the second axis of the inner coupling and the outer member of the second coupling is constrained to rotate angularly in respect of the common member in a way that is the mirror image of the rotation of the inner member of the first coupling with respect to the common member. 
 
     
     
       2. A constant velocity joint as claimed in  claim 1  having a gap between each outer periphery and each inner periphery and one end of each axle is fixed in one of the members and the other end of each axle is supported in a bearing in the other of the members, each bearing having an inner end face acting on the end of the axle supported in the bearing. 
     
     
       3. A constant velocity joint as claimed in  claim 2  in which the gap is 0.5% of an overall coupling diameter of if the overall coupling diameter of is 100 mm or less and 1% of the overall coupling diameter if the overall coupling diameter is more than 100 mm. 
     
     
       4. A constant velocity joint as claimed in  claim 1  wherein the outer peripheries of the inner and intermediate members are convex spherical peripheries and the inner peripheries of the outer and intermediate members are concave spherical peripheries. 
     
     
       5. A constant velocity joint as claimed in  claim 1  wherein
 a central axle is mounted in a first support means, a second intermediate support means, and a third support means, 
 the second intermediate support means being between the first support means and the third support means; 
 the inner annular member of the first coupling is connected to a first housing disposed around the first support means; 
 the outer annular member of the second coupling is connected to a second housing disposed around the third support means; 
 the common member is connected to a third housing disposed around the second intermediate support means; and 
 each housing has an aperture around the corresponding support means in which the support means is mounted. 
 
     
     
       6. A constant velocity joint as claimed in  claim 5  wherein the support means comprise spherical bearings with roller bearings supporting the spherical bearings in the housings. 
     
     
       7. A constant velocity joint as claimed in  claim 6  wherein each support means comprises a boss mounted around the central axle, the boss being mounted in a spherical bearing, a roller bearing being disposed around and supporting spherical bearing in the corresponding housing. 
     
     
       8. A constant velocity joint as claimed in  claim 6  wherein each support means comprises a roller bearing around the central axle, a boss disposed around the roller bearing and mounted in a spherical bearing, the spherical bearing being mounted in the corresponding housing. 
     
     
       9. A constant velocity joint as claimed in  claim 5  wherein the outer annular member of the second coupling is connected to the housing in which the third support means is mounted by a bell-shaped member whose axis coincides with the central axle. 
     
     
       10. A constant velocity joint as claimed in  claim 9  wherein the common annular member is connected to the housing in which the second support means is mounted by a further bell-shaped member whose axis coincides with the central axle. 
     
     
       11. A constant velocity joint as claimed in  claim 1  wherein the intermediate member of the inner coupling and the intermediate member of the outer coupling have the same inertial mass.